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Definition
International Commission on Radiological Protection
each country interprets (UK VERY STRICT) |
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Term
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Definition
radiographs
CT (computed tomography)
Fluoroscopy
Scintigraphy |
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Term
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Definition
Gy: absorbed dose (what causes ill effects)
defined as the absorption of one joule of radiation energy per one kilogram of matter. |
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Term
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Definition
SV: quality factor
one sievert is generally defined as the amount of radiation roughly equivalent in biological effectiveness to one gray (or 100 rads) of gamma radiation |
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Term
| Amount of Gy and Sv in radiation |
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Definition
x-Rays: 1 Gy, 1 Sv
Beta: 1 Gy, 1 Sv
Neutrons: 1 Gy, 10 Sv
Alpha: 1 Gy, 20 Sv |
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Term
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Definition
Lateral Throacic Rad: 0.2 Gy
Atom Bomb: 4.5 Gy |
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Term
| Stochastic vs. Non-Stochastic |
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Definition
| by chance vs. dose dependent effects |
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Term
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Definition
"general effects"
cataracts, skin burns, scarring, carcinogenic |
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Term
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Definition
"biological effects"
effects on descendants of exposed individuals due to mutation of genetic material |
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Term
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Definition
| emitted by electrons, longer wavelengths, lower frequencies, and lower energy than GAMMA rays |
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Term
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Definition
| emitted from NUCLEUS, shorter wavelengths, higher frequencies, higher energy |
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Term
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Definition
Cathode: high speed electrons in vacuum
Anode: abruptly stopped, x-rays emmited
transformers: needed to make voltage |
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Term
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Definition
needs to have high melting point.
high atomic # defined as Z
TUNGSTEN |
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Term
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Definition
kilovolts
potential difference between anode and cathode
controlled by radiographer
POWER/PENETRATION
changes quality |
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Term
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Definition
milliamperes
# of electrons passing from cathode to anode (current)
leads to # of rays emitted
controlledby radiographer
changes quality |
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Term
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Definition
seconds
time of exposure
controlled by radiographer |
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Term
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Definition
milliamperes/second
# of rays/time
governs amount of rays reaching the film |
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Term
| Interaction of rays and subject |
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Definition
Transmission: passes through
Attenuation: gradual loss of intensity while passing through |
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Term
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Definition
Photoelectric effect (absorption based on Z of subject)
Compton Effect (scattering based on density of subject and kV of rays) |
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Term
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Definition
air: black - most passes through
fat: dark grey
soft tissue: soft grey
bone: white
lead: bright white - least passes through |
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Term
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Definition
scatter goes in all direction
decreases with distance (inverse square law)
Grids (stationary, parallel, focussed, Potter-Bucky)
CAN CAUSE NON-SPECIFIC GREYING OF FILM |
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Term
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Definition
FILM not sensitive to x-rays. need INTENSIFYING SCREENS (give off light when hit by x-ray)
DIGITAL done by computed or direct counts |
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Term
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Definition
control area within 2m of tube
if manual restraint necessary: gloves, gowns, thyroid shield, glasses, and film badge
room: 1mm lead shielding or equivalent |
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Term
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Definition
(visibility of details)
controlled by mAs
mAs too low (underexposure) results in a pale film
mAs too high (overexposure) results in a dark film |
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Term
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Definition
(difference in blackness)
kV: low kV gives high contrast
mAs: low mAs gives low contrast |
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Term
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Definition
kV too low (not enough power to get to plate)
mAs too low (not enough rays/time to get to plate) |
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Term
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Definition
| kV too high (too much power) |
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Term
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Definition
blurring at the edge of an object on film (due to rays not all being from same point)
OFD (object to film distance) decrease
FFD (focus to film distance) increase |
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Term
| Nomeclature of radiographs |
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Definition
DIRECTION where beam ENTERS and EXITS
VD 20 degrees RCd: beam goes ventral to dorsal offset by 20 degrees rostral to caudal |
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Term
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Definition
Lat, VD, DV for thorax, abd, skull
Lat, CrCd - limbs |
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Term
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Definition
FML
used in equine rads
DLPMO - dorsal lateral to palmar/plantar medial oblique
DMPLO - dorsal medial to palmar/plantar lateral oblique |
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Term
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Definition
tibia-tarsal bones
Spavin (DJD) |
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Term
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Definition
meta carpo/tasro - phalangeal joints
Chips
DJD
Sesamoiditis |
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